Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered elsewhere. The description adds the downstream-use warning about not guessing a library id, which is genuinely useful, but says nothing about pagination or result ordering despite exposing an offset.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences with the core action front-loaded and no filler. The trailing 'Do not guess a library' is slightly awkward phrasing but still earns its place as a usage constraint.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Because an output schema exists, return values need not be explained, and for a simple read-only list tool the definition is close to adequate. The remaining gap is pagination behavior around offset, which an agent would need before paging through a large library list.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is one parameter (offset) with 0% schema description coverage, so the description carries the full burden of explaining it — and it says nothing about pagination, page size, or what offset means. The mention of a 'returned id' relates to the output, not to the input parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (List) and resource (wording libraries) scoped to 'this account', which distinguishes it from the sibling create_outbound_library. The only weakness is that it never reconciles 'wording libraries' with the tool's own name 'outbound libraries' or with siblings like list_sendable_wording.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Use a returned id. Do not guess a library.' implies this tool is a prerequisite step for other operations, which is useful context. However, it gives no explicit when-to-use versus alternatives and never says when NOT to call it, so guidance is only implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.